Piano construction having a curved back



Jan. 17, 1967 H. E THYEN PIANO CONSTRUCTION HAVING A CURVED BACK FiledApril .20, 1964 v 2 Sheets-Sheet 1 INVENTOR H. E. THYEN ATTORN EYS Jan.17, 1967 H. EJTHYEN PIANO CONSTRUCTION HAVING A CURVED BACK Filed April.20, 1964 2 Sheets-Sheet 2 FIG-3 INVENTOR.

H. E. THYEN ATTORNEYS United States Patent 3,298,268 PIANO CONSTRUCTIONHAVING f i i A CURVED BACK Herbert E. Thyen,

Filed Apr. 20, 1964, Ser. No. 361,067 1 1 4Claims. c1. 84-184) 1 I Thepresent invention relates to pianos, and more par-- ticularly toa pianobackconstruction, especially for upright pianos suchas spinnets, studioconsoles, and the like.

:At present, conventional piano backconstruction of the nature referredto comprise'heavy substantially uniformly spaced posts. arranged.vertically along the ;back

of the pianoand glued, dowelled, or otherwise fixedly Jasper, 1nd,,assignorto W. Kimball Company, Jasper, Ind;,'acorporation of Delaware I3,298,268 Patented Jan. 17, 1967 provided with concave notch means 17extending along secured to upper and lower rail members toprovide'arigid box like construction capable ,of withstandingthe,tensional forcesdeveloped of many tons. by'the piano strings when theseelements'are tightened up'-when., the

'It is apparent that piano backs of. the conventional; type as describedmust necessarily. be-heavily constructed, to provide for the rigidityand strength neededmto -withstand the forcesencountered throughstring-tensioning;-

Conventional piano back constructions therefore con tributesubstantially to the overall weight of the, piano, as well as beingexpensive and complex to construct.

With the foregoing in mind, an object of the present vision of a pianoback construction which is able to.

withstand the stresses and strains encountered in moving of the pianowithout materially effecting the tuning thereof.

A still further object of the present invention is the provision of apiano back construction which is so constructed and arranged as toprovide uniformly distributed reaction against those loads imposed onthe back by forces produced by the tensioning of the piano strings.

A still further object of this invention is the stabilization of thepiano back from the effects of humidity and temperature.

Other objects and advantages of this invention will become more apparentupon reference to the following specification taken in connection withthe accompanying drawings wherein:

FIGURE 1 is a perspective view of an upright type piano as viewed fromthe back thereof;

FIGURE 2 is a partial sectional view taken along line 22 of FIGURE 1 andshowing the novel back construction of the present invention;

FIGURE 3 is a longitudinal section taken along line 33 of FIGURE 1; and

FIGURE 4 is a perspective view illustrating one edge of the piano backconstruction and the manner of assembling,

Referring to the drawings, FIGURE 1, generally indicates at 10 a pianoof the upright type embodying the novel back construction of the presentinvention. The novel back construction, generally indicated at 11,comprises an upper rail 12 having a concave surface 13 extending theentire length of one side thereof, a lower rail 14 having a concavesurface 15 extending the entire length of one side thereof, a pair ofside members 16 thejfull length ;of the inner edges of the side.members, a, slightly arched sounding board 18 having a plurality ofreinforcing rib imembers-21 uniformly spaced therealong on the back, andalaminated, arched support panel indicated by reference numeral 22.Rails 12, 14 and 16 are rigidly interconnected in a known manner to-forma strong frame, s

The .panel22 is fixed the rails, as isthe sounding board 18 to form aunitary 'back' structure. ,The :arched. support panel '22 may' beprovided with a. plurality ofspaced apertures 30 therein whichprovideoutlet means for'tones developed in the resonant chamber 32formed between the sounding board 18 and 'the arched support panel 22;This chamber isindicated in FIGURE 2."-

.- Supportpanel'22 is preferably formedof a plurality of largerectangularxwoodeni-plies laminated in a con-' ventional manner toform-a thick composite board possessing extremetrigidity'and'strength.Hardwood or soft-. wood .veneer'sor combinationsof the two, inspeciessuch 1,; asxu'sed for:.the;cabinet; andasounding board is a suitableThe-preformed-JsupportIpanel '22. is then glued, dowelled material.

The support panel 22 is preformed .to'yan'arched configuration,substantiallyuas shown-in FIGURES l and 2 either at the .time ofilaminating or subsequent thereto orotherwise isecurediat'i itslongitudinal edges at upper and lower regions 24 and 26, respectively,in -matingr relation to curved surfaces 13 and 15 of'upper1an'd lowerrails.12 and 14, respectively. The support panel 22 is also glued,dowelled or 'otherwisesecured' toside members 16 at the exposed edges 28of the panel in mating relation to concave .notc'hmeans 11; Theconventional sounding board 18 is securely positioned to the rails 12,

14 and 16 as indicated at 29 to form the completed piano backconstruction of this invention.

The mechanism necessary for generating the tones delivered to thesounding board 18 is partially shown in-FIGURE 2 of the drawings and isof conventional naturecomprising a multiplicity of strings 34 which arestruck by felt covered hammers 36 and associated means (not shown) togenerate the desired tones. The strings- 34 are connected to the stringplate 38 and pass over a bridge 40 and terminate at a wrest plank 42.

Strings 34'connected between string plate 38 and wrest plank 42 anddisposed over bridge 40 are drawn tightly by'tuning pins 44 to tune thepiano. The total force produced by'the tensioning of the strings is onthe order, as previously stated, of about 18 tons.

v i The arrangement of the present invention eliminates the usualmultiplicity of vertical rails disposed between thetop and bottom railsof a conventional piano back, thus substantially lightening thestructure and making it more inexpensive to construct while not in anyway detracting from the high strength that must be present in a pianoback structure. The arched formation of the back panel disposes it inrelation to the top and bottom and side rails of the piano back so thatit imparts as much strength to the piano back as was formerly obtainedby the heavy vertical rails or posts set between the top and bottomrails inwardly from the ends.

At the same time, the provision of the back establishes the chamberbetween the back panel and the sounding board, which has been referredto above as a resonant chamber and this can substantially enhance thetonal qualities of the instrument even when the curved back panel is notprovided with apertures.

The apertures referred to and illustrated in the drawings in the backpanel are provided when they will improve the tonal qualities of theinstrument and the size and distribution of these apertures will bedetermined by the tonal qualities obtained. These apertures may beuniformly distributed, but it could also be the case that non-uniformdistribution and/or size of the apertures would produce the bestresults.

It will be apparent that the arching of the back panel 22, in additionto giving greater strength to the piano back, also exposes'portions ofthe end rails on the insides that could be availed of for setting inhand grips of a more or less conventional type to assist in the movingof the piano.

The piano back structure according to the present invention is easilycleaned and is not subject to deterioration and is readily adaptable tovarious sizes of pianos. For example, a conventional piano back mightrequire a panel measuring from about thirty inches to somewhat more thanforty inches in height, and this panel might be on the order of sixtyinches in length. In thickness, the curved back panel may vary, and maybe more specific-ally determined by a choice of speciesvof wood veneer,the number of plies, the thickness of individual plies, and the graindirection of these plies. The plies are permanently bonded together witha moisture resistant adhesive and, as mentioned, formed to an archedconfiguration either at the time of laminating or subsequent thereto.The greatest strength can be obtained by curing the panel in its curvedconfiguration. The plies of the laminated back would, of course, bearranged with their respective grain directions crossing, which wouldprovide for the greatest strength of the finished product.

It has been mentioned that the back panel could be glued and dowelled tothe rails, but it is also possible for this member to be secured inposition by large screws, preferably with the use of locating dowels inaddition to the screws.

It will be apparent from the foregoing description, that a piano backconstruction has been provided forming an extremely strong and durablestructure having the necessary properties for withstanding the stressestransferred to the back by the strings 34. Further a piano backconstruction is provided which is neither bulky nor excessively heavy,as compared with present piano back constructions, and wherein the tonalquality of the instrument is not only not deleteriously effected but isenhanced.

It will be understood that this invention is susceptible to modificationin order to adapt it to different usages and conditions; andaccordingly, it is desired to comprehend such modifications within thisinvention as may fall within the scope of the appended claims.

I claim:

1. A piano back construction comprising: a pair of spaced horizontallyarranged top and bottom rail members of substantial cross section, apair of vertically arranged spaced side members secured to the oppositeends of said upper and lower rail members and also of substantial crosssection, said members making up a substantially rigid frame forming theframe of the piano back, sounding board means mounted on said frame onthe side thereof toward the inside of the piano, arcuate groove meansformed along the inner edges of said side members on the other side ofthe frame, a laminated arched support panel mounted on the said otherside of said frame in spaced relation to said sounding board with theconvex side directed towards said sounding board and having itsperipheral portionson said convex side in engagement with said top andbottom rail members and in engagement with said side members at thebottoms of said arcuate groove means, and means fixedly securing theperipheral portion of said panel to said frame.

2. A piano back construction comprising; top and bottom rail members ofsubstantial cross section, side rail members secured to the oppositeends of said upper and lower rail members, and also of substantial crosssection, said members making up a substantially rigid frame forming theframe of said piano back, said top and bottom members being bevelled offtoward the inside of the frame on the one side of the frame which istoward the outside of the piano, arcuate notches formed on the inneredges of said side rail members on said one side of the frame, asounding board mounted on said frame on the other side thereof, tonegenerating means mounted on said sounding board on the opposite sidethereof from said frame and comprising strings, a string plate, a wrestplank, and a bridge, a laminated arched support panel on said one sideof said frame concave outwardly of said frame and having its upper andlower edge portions in engagement with the bevelled loft portions ofsaid top and bottom rail members and having its side edge portionspositioned in said arcuate notches and bearing on the bottoms thereof,means fixedly securing said edge portions of said support panel to saidframe, said support panel being in spaced relation to said soundingboard so as to define a chamber therebetween.

3. A piano back construction according to claim 2 in which said supportpanel has aperture means of substantial size formed therein extendingfrom the concave side of said support panel into said chamber.

4. A piano back construction according to claim 3 wherein said aperturemeans comprise a plurality of apertures distributed over the length andheight of said's'upport panel.

References Cited by the Examiner V UNITED STATES PATENTS 3,001,433"9/1961 Merkel 84-486 FOREIGN PATENTS 87,527 7/1896 Germany.

RICHARD B. WILKINSON, Primdf'y Examiner.

LEO SMILOW, Examiner.

i J. W. HARTARY, Assistant Examiner.

1. A PIANO BACK CONSTRUCTION COMPRISING: A PAIR OF SPACED HORIZONTALLYARRANGED TOP AND BOTTOM RAIL MEMBERS OF SUBSTANTIAL CROSS SECTION, APAIR OF VERTICALLY ARRANGED SPACED SIDE MEMBERS SECURED TO THE OPPOSITEENDS OF SAID UPPER AND LOWER RAIL MEMBERS AND ALSO OF SUBSTANTIAL CROSSSECTION, SAID MEMBERS MAKING UP A SUBSTANTIALLY RIGID FRAME FORMING THEFRAME OF THE PIANO BACK, SOUNDING BOARD MEANS MOUNTED ON SAID FRAME ONTHE SIDE THEREOF TOWARD THE INSIDE OF THE PIANO, ARCUATE GROOVE MEANSFORMED ALONG THE INNER EDGES OF SAID SIDE MEMBERS ON THE OTHER SIDE OFTHE FRAME, A LAMINATED ARCHED SUPPORT PANEL MOUNTED ON THE SAID OTHERSIDE OF SAID FRAME IN SPACED RELATION TO SAID